Comment by NoGravitas

> While there are plenty of non-religious (and thus, small-r rationalist) alternatives to consequentialism, none of them seem to make it past the threshold in these communities.

I suspect this is because consequentialism is the only meta-ethical framework that has any leg to stand on other than "because I said so". That makes it very attractive. The problem is you also can't build anything useful on top of it, because if you try to quantify consequences, and do math on them, you end up with the Repugnant Conclusion or worse. And in practice - in Effective Altruism/Longtermism, for example - the use of arbitrarily big numbers lets you endorse the Very Repugnant Conclusion while patting yourself on the back for it.